These siblings sure do love hanging out with each other!

Shirtless Derek Hough and sister Julianne Hough looked like they were having some sibling bonding time as they soaked up the sun in the French-Caribbean island St. Barth earlier this week.

The bro and sis showed off their toned bodies when they walked around the island and hoped into a bright blue rental car.

We can't help but admiring Derek's sexy six pac! No wonder Kate Hudson can't keep her hands off of the toned dancer ...

Kate seemed to opt out of the Hough family trip to the luxurious island -- but perchance the lovebirds will be reunited on NYE!